vpl - certainly not homework although i did these in school once upon a time. this is for industrial plumbing at work.
i did double check all my unit conversions (gallons to cubic feet, etc). yes the hand calculations
cvg - thanks for the photocopy, this does verify the formula I used. i see...
I have a very simple problem, but I am trying to gain confidence in the calculations for drain down time and flow rate for a free-flow tank drain situation.
I have used free calculators at www.freecalc.com and www.e-funda.com, and I calculated the results by hand from my fluid mechanics notes...